At this point, we actually know a fair amount about how certain behaviors, attitudes, and choices relate to happiness, though most research on the topic can only find correlations.

Researchers think that roughly 40% of our happiness is under our own control; the rest is determined by genetics and external factors. That means there’s a lot we can do to control our own happiness.

Here are nine happiness-promoting behaviors backed by science.

1. Relationships are essential. A major study followed hundreds of men for more than 70 years, and found the happiest (and healthiest) were those who cultivated strong relationships with people they trusted to support them.

2. Time beats money. A number of studies have shown that happier people prefer to have more time in their lives than more money. Even trying to approach life from that mindset seems to make people more content.

3. But it helps to have enough money to pay the bills. People’s well-being rises along with income levels up to an annual salary of about $75,000, studies have found. (That number probably varies depending on your cost of living, however.)

5. Acts of kindness boost the mood. Give your friends a ride to the airport or spend an afternoon volunteering. Some research has shown that people who perform such acts report being happier.

6. Breaking a sweat is about more than burning calories. Studies show that increased levels of physical activity are connected to higher levels of happiness. Exercise tends to help mitigate the symptoms of some mental illnesses as well.

7. Fun is more valuable than material items. People tend to be happier if they spend their money on experiences instead of things. Researchers have also found that buying things that allow you to have experiences — like rock climbing shoes or a new book to read — can also increase happiness.

8. It helps to stay in the present in the moment. Several studies have found that people who practice mindfulness meditation experience greater well-being.

9. Time with friends is time well spent. Interactions with casual friends can make people happier, and close friendships — especially with happy people — can have a powerful effect on your own happiness as well.